Detroit — City firefighters on Friday came to the rescue of a woman who fell into a sinkhole in an alley outside the building that houses The Detroit News.

A building security staffer told The Detroit News that the incident took place around 10 p.m. and fire personnel used a ladder to retrieve the woman in less than 20 minutes.

Building staff said they called police after hearing the woman scream and discovering she had fallen into the hole in the alley between the parking structure that is attached to the Federal Reserve and Chrysler House buildings in Detroit's downtown.

A man was also seen climbing up the fire ladder Friday to exit the sinkhole. Witnesses said he went in after the woman to help her.

A woman late Friday fell into a sinkhole behind the building that houses The Detroit News.(Photo: Julie Walker Altesleben)

Officials said they believe the sinkhole is about 20 feet deep and had been blocked off along Griswold with two dumpsters and fencing with a sign that reads: "Danger Do Not Enter Sinkhole."

Detroit Police officers on the scene said the woman sustained very minor injuries and no arrests were made. The woman was transported to Detroit Receiving Hospital. The man was not injured.

The alley off of Griswold downtown is blocked with dumpsters, a gate, fencing and a sign, warning of the sink hole(Photo: Julie Walker Altesleben)